

REPTILIA. DINOSAURIA. 207 



1. anterior nares. 5. scapula. 



2. prominence on the nasal 6. coracoid. 



bones which probably 7. ilium. 



carried a horn. 8. pubis (pre-pubis). 



3. pre-orbital vacuity. 9. ischium. 



4. orbit. 



The nares have the form of long slits and there are large 

 pre-orbital vacuities. 



The limb bones are solid, and the anterior limbs are not 

 much shorter than the posterior ones. All the limbs are 

 plantigrade and pentedactylate, and the digits of the pes are 

 clawed. There is a large pre-pubis directed downwards and 

 forwards, meeting its fellow in a ventral symphysis, but there 

 is no post-pubis. 



The Sauropoda are found in the secondary rocks of Europe 

 and N. America and include the largest land animals that are 

 known to have existed. Many of the best known forms such 

 as Brontosaurus and Morosaurus are North American. 



Suborder (2). THEROPODA. 



The members of this suborder were all carnivorous, and 

 from the small comparative size of the anterior limbs many of 

 them were probably bipedal. 



The vertebrae are opisthocoelous or amphicoelous, their 

 neural arches are provided with zygosphenes and zygantra, 

 and their centra are frequently hollowed internally ; the limb 

 bones are also hollow, and in fact the whole skeleton is ex- 

 tremely light. The tail is of great length. The teeth are 

 pointed and recurved, and have one or both borders serrated ; 

 they are always planted in distinct sockets, and some of them 

 are borne by the premaxillae. There are large pre-orbital 

 vacuities. The digits of both manus and pes are terminated 

 by pointed ungual phalanges which must have borne claws. 

 In the pelvis the pre-pubes and ischia are slender bones, the 



